JPH02134876A - Solar battery module - Google Patents

Abstract

PURPOSE:To provide the title module that is capable of electric power to load without interruption without providing a secondary cell anew by employing a thin secondary battery on at least part of a module substrate. CONSTITUTION:In a solar battery module wherein a plurality of solar battery elements for photoelectric direct conversion are combined serially or parallely and disposed on a substrate to provide predetermined voltage, a thin secondary battery is used on at least part of said substrate. For example, there are formed on a thin secondary battery substrate 35 a wire 14, an electrode 15, and a crystalline silicon layer 16 to construct a crystalline silicon solar battery module. For the thin secondary battery, there isavailable ones wherein comb-shaped positive electrode member 42 and negative electrode member 43 are disposed parallely on one surface of a flat plate-shaped substrate 41A., and a space between the positive and negative electrode members 42, 43 is filled with an electrolyte 44 associated with a battery reaction, and further a cover member 41B is connected to the substrate 41A, covering the electrode members 42, 43 to constitute a battery casing 41.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel solar cell module, and particularly to a solar cell module using a thin secondary battery in at least a portion of a module substrate.

[Prior Art] A solar cell is a device that utilizes inexhaustible solar energy and performs direct photoelectric conversion using the photovoltaic effect, which is a quantum effect of semiconductors.

When light (photons) with appropriate energy intensity enters a semiconductor, the light interacts with the lattice that makes up the semiconductor, generating electrons and holes. p-n in semiconductor
When there is a junction, electrons diffuse into the n-type semiconductor, holes diffuse into the p-type semiconductor, and they gather at the picture electrode portion. When these picture electrodes are connected, current flows and power can be extracted. Solar cells (1) can generate electricity using inexhaustible solar energy, (2) do not generate hazardous waste or noise, (3) can generate electricity in the same place as electricity. 4) It has excellent advantages such as being able to generate electricity not only under direct sunlight, but also from sunlight on cloudy days and indoor light, and the photoelectric conversion efficiency generally does not change much depending on the intensity of light. .

For this reason, solar cells are currently made by combining multiple solar cell elements in series or parallel and arranging them to obtain a predetermined voltage, as well as using support plates, fillers, coating materials, etc. to withstand the surrounding environment. In the form of protected solar cell modules, it is widely used in various electronic products such as calculators, watches, radios, chargers, electronic games, etc.

In addition, social factors such as consumers' desire for cordless products and the desire to eliminate the hassle of changing batteries, and the reduction in power consumption of electronic products due to the development of IC or LSI This is being driven by technological factors such as the development of increasingly smaller solar cells and the development of low-cost integrated amorphous solar cells that can produce high voltages on a single substrate, making them suitable for use in electronic products. I'm putting it on.

Single-crystal silicon solar cells are typically made by thermally diffusing n-type impurities into a p-type silicon single crystal to form a single-crystal silicon layer with a pn structure, and then forming a comb-shaped lead electrode (for example, a silver electrode) on top of the single-crystal silicon layer. An electrode (for example, a silver electrode) is baked and applied under the single crystal silicon layer.

Glass substrate type amorphous silicon solar cells are
A transparent conductor (transparent electrode) is formed on the glass substrate,
Next, three amorphous silicon layers of p-type, i-type, and n-type are formed by plasma reaction, and then a metal electrode layer (for example, an aluminum layer) is formed.

A metal substrate type amorphous silicon solar cell is a metal substrate (typically stainless steel) that is
An n amorphous silicon layer is formed, a transparent conductive film (transparent electrode) is formed thereon, and a comb-shaped lead electrode (for example, a silver electrode) is formed.

In a glass substrate type amorphous silicon solar cell module, each cell formed on one insulating substrate (glass substrate) is connected in series with the adjacent cell through a transparent electrode and a back electrode by appropriate patterning. and high voltage can be obtained.

Among the metal substrate types, there is a tandem type (multilayer structure) cell that takes advantage of the characteristics of an amorphous silicon large-millimeter cell by stacking cells vertically on a metal substrate and providing a transparent electrode thereon.

[Problems to be Solved by the Invention] When solar cells are installed in devices, devices that are used only in bright places, such as liquid crystal display calculators, use only solar cells as an independent power source.

However, solar cells can only generate electricity when there is sunlight, and they do not have a power storage function, so they need to operate even in places where there is no incident light, such as watches, radios, chargers, etc. The device is equipped with a backup secondary battery as a backup power source.

FIG. 4 shows a circuit configuration when a solar cell is used with a secondary battery added thereto. Sun from the secondary battery 33 by the backflow prevention diode 30? The voltage control circuit 32 or current limiting resistor 31 prevents current from flowing to the secondary battery 3.
3 prevents overcharging.

When the solar cell operates using sunlight or indoor light, power is supplied from the solar cell 29 to the load 34 and the secondary battery 33 is charged.

When there is no light irradiation and the solar cell does not operate, the load 3 is transferred from the secondary battery 33 charged by the solar cell 29.
4. Power will be supplied without interruption. Note that in an actual circuit, the current limiting resistor 31 and the voltage control circuit 32 are not used at the same time, but one of them is used.

Currently, as the backup secondary battery 33, silver oxide batteries are mainly used in watches, and nickel cadmium batteries are mainly used in radios and chargers. However, when these secondary batteries are added in addition to the solar cells, additional space is required, and the number of overlapping devices increases, which poses a major hindrance to reducing the size and weight of devices.

The present invention aims to solve the above-mentioned problems and provide a solar cell module that can supply power to a load without interruption without providing a separate secondary battery. .

[Means for Solving the Problem] In order to achieve such an object, the present invention provides a structure in which a plurality of solar cell elements that perform photoelectric direct conversion are combined in series or in parallel on a substrate so that a predetermined voltage can be obtained. The solar cell module arranged in the solar cell module is characterized in that a thin secondary battery is used for at least a part of the substrate.

[Function] According to the present invention, a plurality of solar cell elements that perform direct photoelectric conversion using the quantum effect of semiconductors are arranged in series or in parallel so as to obtain a predetermined voltage, and are resistant to the surrounding environment. By using a thin secondary battery as at least a part of the solar cell module substrate protected by a support plate, filler, coating material, etc., it is possible to reduce the size and weight of the device.

[Example] Examples of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows an example in which a thin secondary battery is used as the substrate of a crystalline silicon solar cell module. Wires 14, electrodes 15, and crystalline silicon layers are formed on thin secondary battery substrate 35. 36 is the positive terminal of the thin secondary battery, 37
is the negative terminal of the thin secondary battery. Note that the positions of the terminals 36 and 37 can be arbitrarily set according to the conditions of use.

The thin secondary battery substrate 35 and the solar cell electrode 15 are insulated by the insulating coating material of the thin secondary battery. In terms of manufacturing, there is no particular difference from the conventional manufacturing method, as the solar cell is simply formed on the thin secondary battery substrate 35 instead of the conventional substrate.

FIG. 2 shows another embodiment in which a thin secondary battery is used as the substrate of a metal substrate type multilayer amorphous silicon solar cell module. Reference numeral 38 designates a thin secondary battery substrate coated with a metal to ensure electrical conductivity and to function as an electrode of a solar cell, or a thin secondary battery substrate housed in a metal case. Amorphous silicon layer 27 on substrate 38
is formed, and a transparent electrode 25 is formed thereon.

39 is a positive terminal of the thin secondary battery, and 40 is a negative terminal of the thin secondary battery. In this case as well, the positions of the terminals 39 and 40 can be arbitrarily set according to the usage conditions of the solar cell module, as in the above embodiment.

The terminals 39 and 40 of the thin secondary battery and the transparent electrode 25 of the solar cell are insulated. In terms of manufacturing, there is no particular difference from conventional manufacturing methods, as the solar cells are simply formed on a thin secondary battery substrate instead of a conventional substrate.

Note that in the case of a glass substrate type amorphous silicon solar cell, the substrate must pass light, so a thin secondary battery cannot be used instead of the glass substrate. When applying a thin secondary battery to a glass substrate type amorphous silicon solar cell, a separate battery must be provided behind the back electrode.

Although crystalline silicon solar cells and amorphous silicon solar cells have been described above, the present invention can also be applied to other types of solar cells that are currently in practical use, such as compound semiconductor solar cells and organic semiconductor solar cells. .

An example of a thin secondary battery applied to the present invention is 111 m
For example, there is a thin secondary battery described in Japanese Patent Application No. 185085/1985 which can be made as thin as the following. This thin secondary battery includes a positive electrode member and a negative electrode member that are arranged substantially in the same plane so that their end faces are separated and face each other, a substrate that fixedly supports the positive electrode and the negative electrode member, and a sealed container that includes the positive electrode and the negative electrode member. A cover member that defines the chamber together with the substrate, and an electrolyte that participates in the battery reaction between the positive electrode member and the negative electrode member housed in the sealed chamber so as to be present between at least the opposing end surfaces of the positive electrode member and the negative electrode member. There is. In order to increase the area of the opposing end surfaces of the bipolar members (i.e., the effective electrode area), the opposing edges of the picture electrode members when viewed in plan are formed into a corresponding comb shape, waveform (triangular wave, rectangular waveform, etc.), or spiral shape. Preferably, the shape is In this secondary battery, the positive electrode member and the negative electrode member are not arranged in the thickness direction as in the conventional case, but are arranged side by side on the same plane, and the end surfaces of the picture electrode member are spaced apart and facing each other. It has an important feature in that it is

Therefore, the thickness of the battery can be reduced.

In other words, when the battery has this structure,
The direction in which the battery reaction field develops during charging and discharging is parallel to the electrode surface, so even if a thin electrode member is used, the current collecting part will not be lost due to charging and discharging, and the battery can be made thinner. .

The thin wooden battery will be specifically explained using FIG. 3(A) to FIG. 3(C).

Figures 3(A) to 3(C) are patent applications filed in 1985-185.
1 shows a first embodiment of the thin secondary battery described in No. 085. 3(B) and 3(C) show cross sections of the battery shown in FIG. 3(A).

As shown in FIG. 3(A), on one surface (plane) of the flat substrate 41A, a comb-shaped positive electrode member 42 and a negative electrode member 43 are arranged in parallel, respectively, as will be described in detail later. The space between 42 and the negative electrode member 43 is filled with an electrolyte 44 that participates in battery reactions. The positive electrode member 42 is
The negative electrode member 4 is formed of a positive electrode material containing a positive electrode active material.
3 is formed of a negative electrode material containing a negative electrode active material. In the case of lead-acid batteries, the positive electrode active material is lead dioxide;
The negative electrode active material is lead. As the electrolyte 44, a liquid electrolyte such as sulfuric acid can be used.

A cover member 41B is coupled to the substrate 41A, covering the electrode members 42 and 43. The cover member 41B and the substrate 418 constitute a battery case 41 that defines a sealed chamber. The substrate 41A and the cover member 418 exhibit insulating properties at least on their surfaces, and are made of, for example, an acid-resistant polymer material such as acryloni I-lylubutadiene-styrene resin (HeBS resin), a fluorine-based resin, or a brass tink material. Alternatively, it can be made of glass woven δ (F-reinforced plastic material).Furthermore, in order to prevent the permeation of moisture contained in liquid electrolyte such as sulfuric acid, a laminate in which a metal layer such as aluminum is coated with an insulating polymer material is used. The substrate 41A and the cover member 41B may be formed of a polyvinylidene chloride resin (PVCD resin) or a polyvinylidene chloride resin (PVCD resin). A safety valve 45, a positive terminal 46, and a negative terminal 47 are provided.

As shown in FIG. 3(B), the positive electrode member 42 is comb-shaped, and a plurality of rectangular teeth 428 having substantially the same shape extend from a comb bone 42B at predetermined intervals. The negative electrode member 43 is also comb-shaped, and a plurality of rectangular teeth 43A having substantially the same shape extend from a comb bone 43B at predetermined intervals. Each of the teeth 428 of the positive electrode member is inserted between the teeth 43A of the negative electrode member without contacting with I#43A of the negative electrode member. In this way, the positive electrode member 42 and the negative electrode member 43 are arranged such that their end surfaces face each other.

FIG. 3(C) (Here, for convenience of explanation, the thickness d of the positive electrode rectangular tooth 42A and the negative electrode rectangular tooth 43A are shown extremely enlarged compared to their widths, but the actual 13 (The thickness d is extremely smaller than the width l between the electrode members 42 and 43), the cover member 41B closely covers the surfaces of the electrode members 42 and 43, The electrolyte 44 is connected to the electrode members 42 and 43 and the cover member 41.
It does not penetrate between the contact surfaces with B and attack this surface.

In the above-described secondary battery, the positive electrode member 42 and the negative electrode member 4
3 are arranged side by side on the surface of the substrate 41A, that is, on the same plane, so compared to a conventional secondary battery in which these members are arranged in the thickness direction, the thickness is the same as that of the conventional battery. Even when a small electrode member is used, the thickness of the present secondary battery can be reduced to about 173 mm, which is the thickness of a conventional battery.

Conventional thin secondary batteries, such as the conventional thin sealed S9 storage battery, have a structure in which the main components of the battery, such as a positive electrode plate, a negative electrode plate, and a separator, are arranged in the thickness direction. . In order to reduce the thickness of a battery having such a structure, the positive electrode plate, the negative electrode plate, etc. may be made thinner, but there are limits to this as described below. In the conventional secondary battery having the above structure, the battery life largely depends on the thickness of the electrode plate (especially the positive electrode plate). That is, as is well known in the art, as the thickness of the electrode plate decreases, the battery life decreases.

The relationship between the thickness of the electrode plate and the battery life under trickle charging in a conventional lead-acid battery having the above-mentioned structure is that the life of a conventional battery decreases rapidly as the thickness of the electrode plate decreases; When the thickness of the battery becomes 1 mm or less, it becomes almost impossible to use it repeatedly as a secondary battery.

This is because, in conventional secondary battery structures, the field of battery reactions that occur during charging and discharging develops in a direction perpendicular to the main surface of the electrode plate (thickness direction). .

In other words, in order for a battery to function as a secondary battery, a part that does not participate in battery reactions, that is, a current collecting part, must always be present in the electrode, but as the thickness of the electrode plate becomes thinner, During charging and discharging, this current collector disappears, making it impossible to function as a battery. This situation is exactly the same when cycling a battery. For these reasons, for example, in conventional thin sealed lead-acid batteries, the limit for reducing the overall thickness of the battery is 4 to 5IllI11.

In addition, as shown by the arrow in FIG. 3(C), in this secondary battery, the direction in which the battery reaction field develops during charging and discharging is perpendicular to the thickness direction of the electrode member, unlike in conventional batteries. direction (i.e. parallel to the width of the electrode teeth). Therefore, the width of the rectangular teeth (M-position electrode) 42A and 43A is 1 to 2 m.
m or more, for example 3 to 4fflI11, but if this is done, the electrode thickness d will be 1 mm or less,
For example, even if the thickness is 0.1 mm or less, a battery life equal to or longer than that of conventional thin secondary batteries can be ensured.

That is, in the secondary batteries shown in FIGS. 3(A) to 3(C), even if a thin electrode member with a thickness of d is used, by increasing the width A, the current collecting portion during charging and discharging can be reduced. Disappearance can be suppressed. Other thin secondary batteries that can be applied to the present invention include the following embodiments.

The secondary battery of the second embodiment differs from the secondary battery of the first embodiment only in that the cover member 41B is disposed apart from the upper surfaces of the electrode members 42 and 43.

Although the battery life of the secondary battery of the second embodiment is substantially the same as that of the secondary battery of the first embodiment, it is easier to manufacture since it is not necessary to bring the cover member 41B into close contact with the electrode members 42 and 43. It's easy. Note that this secondary battery can also be made thinner, to about 173 cm, compared to conventional batteries.

A lead-acid battery will be described as a specific example of this battery. It is 0.65mm thick, 50mm long, 78mm wide, and weighs 4.
．． 7kg; volume 2.5cm', electrode member thickness 0.4m
The discharge curve of the lead-acid battery, which is rn, shows the voltage change over time peculiar to lead-acid batteries, and the battery capacity is approximately 40n+.
The value of Ah was obtained. Furthermore, the durability is sufficient, and the present secondary battery has characteristics that can be put to practical use.

In the secondary battery of the third aspect, a positive electrode member and a negative electrode member facing each other at a distance form one single cell.1. ．． It has a structure in which three single cells are connected in series. A thin plate-shaped positive electrode member and a thin plate-shaped negative electrode member are arranged on a substrate, and the positive electrode members and negative electrode members of adjacent single cells are provided in contact with each other, and between them, the battery No reaction occurs. In addition to the effects of the secondary battery according to the first embodiment, this secondary battery has the effect of being able to obtain a battery voltage three times higher than that of the secondary battery according to the first embodiment.

In addition to the above-mentioned secondary battery, the positive electrode member and the negative electrode member may each be formed into a thin, substantially sinusoidal pattern. Further, the positive electrode member and the negative electrode member may each be formed into a thin sawtooth shape (triangular wave shape).

Furthermore, the positive electrode member and the negative electrode member may each have a thin spiral shape.

In addition, in this secondary battery, the positive electrode member and the negative electrode member are fixed on the substrate, so there is no need to provide a separator between them, which was required in the past. It may be provided between the member and the negative electrode member.

[Effects of the Invention] As explained above, according to the present invention, by using a thin secondary battery in the module substrate, it is possible to supply power to a load without interruption without providing a separate secondary battery. It is possible to realize a solar cell module that is capable of this, and it is possible to make the equipment smaller and lighter.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention in a crystalline silicon solar cell module, FIG. 2 is a diagram showing another embodiment of the present invention in an amorphous silicon solar cell module, and FIG. 3 (8) is a partially cutaway perspective view of the first embodiment of the thin secondary battery applied to the present invention; FIG. 3(B) is a horizontal sectional view of the secondary battery shown in FIG. 3(A); (C) is a sectional view taken along the line III--III in FIG. 3(B), and FIG. 4 is a circuit diagram when a solar cell is used with a secondary battery added thereto. 16... Crystalline silicon layer, 25... Transparent electrode, 27... Amorphous silicon layer, 35.38... Thin secondary battery substrate, 35.39... Positive electrode terminal, 37.40...・Negative terminal.

Claims (1)

[Claims] 1) In a solar cell module in which a plurality of solar cell elements that perform photoelectric direct conversion are arranged in series or in parallel on a substrate so as to obtain a predetermined voltage, a thin secondary battery is provided on at least a portion of the substrate. A solar cell module characterized by using